'99 Electrical problems

Believe these all coincide. My 99 Taurus electric door locks work-sometimes. Lately the car will refuse to start like the battery is dead, nothing. Fiddling with it, cleaning contacts etc sometimes works but last time even jumping from another vehicle car had same symptoms. Tells me its not the battery. Today while driving on freeway at 55 on a left hand curve car momentarily died, idiot lites flashed, radio reset to AM all like I just broke the battery connection. Was thinking the ignition switch maybe?

Welcome to the forum!

Is the battery properly secured? Do the battery cables fit snugly on the battery, so snuggly that if you grab on to them and attempt to rotate the cable around the battery post it won't move (when using reasonable torque)?

If the battery is not or has not been securely attached to the car, it could be bouncing around and either shorting mometarily against some metal part of the car, or a plate may have broken internally from bouncing and be causing the momentary open circuit. Under heavy loads when this happens, the alternator may not be able to keep up.

Seems far fetched, but something to look into. If all that checks out, then as you suspect, you are probably looking for a loose connection somewhere.

-Rod

Something to consider. I had similar issues with my 98 Taurus. I thought the battery was fine as well. I took it in and had the battery tested, turned out it had a burned out cell. A new battery resolved the problems. Just a thought.